INTRODUCTIONSag tension calculation is carried out to estimate the sag in the conductor under varioustemperatures. The calculation is carried out for the conductorspan lengths in use in 765kVINPUT DATAInput data required for carrying out the calculations are as followsInitial tensionc!c distance of tower"#pansion coefficient$%&"lasticity modulas $"&'o. of stringsweight of string'o. of conductos $n&String length $(S&PARAMETERS USEDl ) half span length of conductor*) span lengthf+ ) Stress at Temprature ,+-elow end of stringf. ) Stress at Temprature ,.-elow support conductor at Temprature ,+ conductor at Temprature ,./) 0alf inclined length of conductor span12) "quivalent conductor weightBASIS OF CALCULATIONTension at any temperature 2 e! Ca&the equation to -e solved is as follows3conductor diameter $dc&conductor 4rea $4c&girder width $lg&tower height $h+&tower height $h.&5ind 6ressure on cond $6wc& 7iameter of string insulator $di&5ind 6ressure on insulator $6wi&string weight! conductor $5wi&8onductor weight $1c&spacer weight $1s& 8onductor chord length $lc&,+ ) Initial Temperature 5wi ) "quivalent weight of insulator with wind,. ) final Temperature7+) Sag at centre of insulator catenary27.) Sag at centre of insulator catenary2w+) "quivalent weight of 79 ) 8onductor Sag -elow end of insulator stringw.) "quivalent weight of5wi) wind load7: ) total Sag insulator plus conductorT+ ) Tension at Temprature ,+T. ) Tension at Temprature ,. /+ ) 6ro;ected *ength of S6ns) 'o. of spacers /.) 6ro;ected length of S6? @ A22 216Tl1w Ewhere >@ f+) )$,. ),+&%"A @f+@-&*oading due to wind on conductor and insulator3c&*oading due to self weight of the conductor and spacers3weight of the spacers has -een considered alongwith the weight of the conductor.The equivalent weight of the conductor and spacers is given -y3where12 @ weight of the su- conductorn @ no. of su- conductor"quivalent weight of the conductor in the loaded condition3equivalent weight of conductor under full wind condition is given -yd& 1a#imum sag$7:&(efer >ig +whereT3 tension in kg!conductorstring length/ @ $l)(S& / +.BBB5$assumed&w..l."64c.T+!4c5ind loading 5wc @ 6wc # dc for conductor5ind loading 5wi @ 6wi # di for insulator12 @ 12c < $ns.1s&!$n.lc&C.. 4s per I"8 ) D65ns@ no. of spacers1s @ weight of the spacerlc@ chord length of the conductor $ total span less the girder width and length of the insulator string&w+ @ =$12&. < $5wc&.?a+@ T!5+ for conductor catenarya.@ T!5wi for insulator catenary5+ 3 equivalent conductor weight5+ @ no of string # string weight/+ @ a. /a+(S6 @ (S < S6/9 @ /. ) /+/ @ +!. E +)/9a.a.a+Sag 7: @ 79 < 7. ) 7+e& 6oint of 1a#imum sag from the Support towers. wl. wl(eference3 Te#t Fook3GA"'"(4TIH'I T(4'S1ISSIH' 4'7 JTI*IK4TIH' H> "*"8T(I84* 6H5"(G)4.T.ST4((S6 @ a. sinh /+a./. @ a. sinh)+(S6a.7+ @ a.$ cosh/+ ) +&(ef page 5: of Te#t -ook GAeneration Transmissionand JtiliLation of "lectrical 6owerG )4.T.ST4((7. @ a.$ cosh/. ) +&79 @ a+$ cosh/ ) +&/6+ @+ l < Th/6. @+ l < ThSAMPLE CALCULATIONCir"uit # $%&'( )ua Moose *+, m span-.enera/ DataInitial tension..5B kg.!condc!c of tower +B: mAirder width lg . mc!c tower ) leg +B: mTower 0eight 9M m+9M.7: (ef 4''"/J(")I+7..BD (ef 4''"/J(")IConu"tor Data'o. of conductors$n& :..: Ng!m9.D9")B. m8onductor 4rea $4c& B.BBBD65 sq.m"#pansion 8oefficient$a& B.BBBB.9 deg8 as per IS 9MD $6)III)+M76&"lasticity 1odulus$"& :.7+"f..)A@BG for f.'owI f.9)>f..)Awe get f.kg!m.@ .5:BD57.5++ # B.BBBD65:1en"e 4 2*563$%'!d& Sag under full wind conditions ) Initial temperature B deg 8Sag point /6+ @ +!. # $*& /6+ @ 5. mwith reference to fig + and equations given under section :.9a+ @T+ @ ..5B @ 97D.+5w+ 5.M5BBa. @T+ @ ..5B @ 6D.M9wi .56.955!7.D5:/$ass& @ $$l).&!.)(S& # +.BBB5 @ $$+B:).&!.)7.D5:+.BBB5@ :9.+7 m/+ @ $a.!a+& /@ $6D.M9:!97D.+5+:9.+6D@ 7.D7S6 @@ 6D.M9:#SI'0$7.D6M!6D.M9:&@ 7.DM(S6 @@ 7.DD6 I'7I4 *I1IT"7765!:BBkV (4I6J( '"5 R :BBkV (4I6J( "/T'. S!S5I'7 6("SSJ(" 84*8J*4TIH' >H( 8H'7J8TH( R I'SJ*4TH( ST(I'ANote # Ma